Working with Oversized Metal Panels

Transportation, handling and installation tips for oversized panels

By Mark RobinsSenior EditorPosted May 01, 2018

With the growing trend of glass manufacturers fabricating longer and wider sheets of glass, architects are designing more of their projects with larger metal panel sizes. These oversized metal panels have special transportation, handling and installation requirements.

Mishandling oversized metal panels can negatively affect both their performance and aesthetics. “Long-length panels have the tendency to buckle or fold if not sufficiently supported,” says Jeff Haddock, technical representative, AEP Span, Fontana, Calif. “This can put creases in the panel legs or the panel giving an unsightly appearance. Damage to the panel leg can also affect panel performance—weathertightness and wind uplift—by not allowing the panel’s male/female leg to fully engage.”

Oversized panels are not only longer, but they also weigh more. These two components make individual panels and bundles that are much more susceptible to damage. “Buckling and kinking are the best way to describe the most commonly seen damage,” says Brian Shelton, marketing manager, Chief Buildings, Grand Island, Neb. “It is also common to see localized bends and evidence of crushing at lift points and blocking/dunnage points when stacked. If sliding and articulating clips are not used or installed correctly, the added expansion and contraction of the long panels may create stress risers and lead to panel failure.”

Oversized Panel Transportation

Generally, flatbed trailers are 48 feet long. Material on these trailers is allowed to overhang the trailer’s end by 5 feet. This allows for maximum panel lengths of 53 feet to be shipped on standard flatbed trailers.

Riess Construction and Oversized Panels

Long panels can sometimes hang over the rear of the truck and sometimes dedicated trucks are necessary, driving up freight cost. Properly sizing cranes or forklifts with spreader bars is very important. No fun showing up to a site to unload and not having the right equipment then buckling a bundle of roofing or siding trying to get by with the wrong rigging or equipment. Having a large, and most importantly, flat lay-down area is key. Have enough manpower and the right-size boom or scissor lift to keep backs from being stressed and guys safe. Oversize spreader bars and even trailers can move panels around job sites. Sometimes we use a jib on a forklift and pick up the panels from the end if the panels are too wide to navigate smaller sites.

Longer panels may require stretch load trailers.
“Stretch load trailers can handle loads of up
to 100 feet long,” Haddock says. “Special consideration
must be taken into account regarding
the shipment of stretch trailer loads. Job sites in
remote or mountainous areas can be very challenging
to access with long trailers due to tight
turns. Job sites also have a finite amount of area
to handle larger-than-normal loads.

Steve Arnold, vice president of operations at
Queen City Roofing and Sheet Metal, Springfield,
Mo., stresses when transporting panels to make
sure they are properly strapped down with foam
or other soft materials in between the panels.
“Delivering the longer panels takes special trucks
and permits to ship longer panels,” he says. “If at
all possible, we find it’s better to order coils and roll
our own panels on-site.”

Oversized Panel Handling

To prevent damage, extra caution and care
should be exercised due to the added bulk and
weight of oversized panels. Comprehensive
training of employees with panel manufacturer
information also helps. Haddock contends an installer’s
ability to handle oversized panels should
be carefully considered before a project is bid.
Safety procedures must be in place to accommodate
any oversized panel.

PCL and Oversized Panels

PCL Construction recently completed an entertainment project in Orlando, Fla., that included oversized metal panels. There were two different types of exterior insulated metal panels (IMPs) on the project, one with a foam core and the other with mineral wool. The panels were up to 45 feet in length and were 42 inches wide. The metal wall panels were unloaded with a crane and spreader bar with multiple lift points to prevent bending of the panels. Storage of metal panels on-site was limited as much as possible due to the tight site constraints. Bundles of panels were staged per the erection phases, minimizing double handling.

The erection crew utilized vacuum equipment to lift and attach the metal panels to the building structural members. The vacuum equipment was attached to the crane and had a redundant secondary safety line to the panel. The erectors worked off two-man lifts to fasten the panels to the building. The vacuum equipment increased the speed of erection from the time the team initially hooked up to the panel through the time they fastened it to the structure. If oversized metal panels are not properly handled with sufficient lift points on each panel, the panel can become bent or fail to the point that it is unusable. Sufficient lift points are critical when installing oversized metal panels.Chance Barnes, project manager, PCL Construction, Orlando, Fla.

Photo courtesy of Chief Construction

Photo courtesy of Chief Construction

Trident and Oversized Panels

To handle an 80-foot panel takes four men in the shop so you don’t bend the panel when you are taking it off the rollforming machine. An 80-foot panel usually takes five men to install, but you save your labor on the end laps. If you had two 40-foot panels you could get by with three men, but it would take you twice as long because you lap it and do the whole end-lap sealing detail in the back-up piece that you fasten into. If you can avoid an end lap, it saves labor.

During installation, oversized metal panels are more susceptible to wind pick-up on a roof. There’s more temporary strapping to do on a larger span. For an 80-foot metal panel, you would have to temporarily fasten it down in five locations; a 40-foot panel only two locations. Customers like long-span panels because you eliminate a possible source of a leak with expansion/contraction.Willard Petrat, vice president of operations, Trident Building Systems, Sarasota, Fla.

Nathan Libbey, division III manager at Best Buy Metals, Cleveland, Tenn., says oversized panels usually require special crating or multiple forklifts to offload or load. Mike Wallace, president of Quality Metal Crafts LLC, Rogers, Minn., says the crates need to be reinforced to withstand the additional weight and also be built in such a fashion that makes loading and unloading a simple process for when the material arrives on-site. Larger tarps may be required to ensure oversized panels are kept dry on the job site.

Rodney Hiller, sheet metal superintendent at Queen City Roofing and Sheet Metal, agrees that in addition to bigger equipment like lifts, cranes, vacuum lifts and panel rollers, a key to handling oversized panels is limiting the times you must move them. Also, “Make sure you have plenty of manpower when handling oversize panels,” he adds.

Trent Tyler, steel supervisor at Chief Construction, Grand Island, says a spreader bar and rigging should be used when handling or moving panels at the job site. “This will help eliminate difficult maneuvers through difficult corridors,” he says. “Bundle placement while stored or in preparation for installation is important to minimize handling. Installation begins once the bundles are broken and it is more difficult to move single panels without damage and caution is advised. One example: an architectural vertical rib standing seam panel will need to be stood on its side, secured face to face with another panel while lifted with a wide spreader bar and rigging. When picking bundles with lifting straps, it is advisable to use flat plates in conjunction with your rigging to prevent crushing the corners of your material.”

Hiller recommends having a good game plan before you start your job and definitely having a morning huddle with the crew who will be handling and installing the panels before starting on that day. “It is important to let the crew know the importance of these oversized panels not being damaged during the project,” he says. “Explain to them the costs of the panels and how hard it is to get replacement panels. You can’t just expect the crew to know these things. Communication is always the best way to avoid problems in the field.”

Oversized Attachment Advice

When installing metal panels, it’s important to understand how they are attached to the substrate, or these days, more likely the substructure (i.e., cladding attachment system). When large areas of opaque wall are covered with a single panel, all of the wind load from the area the panel covers is funneled down into the connections around the perimeter (typically). Therefore, those connections end up feeling a substantial point load and are generally engineered on a job-by-job basis.

It is crucial to be sure the entire wall system underneath the panel is designed for the reaction these point loads induce for structural stability. It is not safe to assume the load will always be dispersed evenly and uniformly to the substrate/substructure, and by doing so may lead to structural deficiencies and frankly a dangerous situation.Brian Nelson, general manager, Knight Wall Systems, Deer Park, Wash.

Photo courtesy of Queen City Roofing and Sheet Metal

Accurate Oversized Installation

According to Tyler, oversized, through-fastened
metal wall panels are installed in one of two ways.
One way is to pull the panel up with a rope and a
device to secure them together. “Drilling a hole
in the top of the panel that will later be covered
by trim offers a method of attachment,” he says.
“When doing it this way you will need to consider
additional support for the middle of the panel to
prevent bow outward or possibly buckling the
sheet. Alternatively, taking the top of the panel up
in a man lift while personnel hold the bottom from
the ground is a proven method to get to the full
upright position. It may be necessary to support
the panel 6 to 10 inches from the top of the panel
to reduce the distance between support, and
prevent bow out and buckling on the way up. Once you establish how to lift, you will need to decide if there will be any bow out in the panel as you are setting the initial fastening points (wind, insulation).
This can be minimized with personnel on a second
lift at mid-height. Moving your initial fastening point
from the top down one girt level will decrease the
distance to the initial bottom fastening point.”

Maintaining proper laps and edge alignment is
requisite when oversized metal sheets are installed,
as any misalignment at one end translates
into a major misalignment at the other end. “Additional
man lifts may also be warranted in wall applications,
primarily to maintain control of the panel at
mid-height during installation, but also to limit bow
out,” says Shelton. “If bow out is not controlled
and screw installation sequence is haphazard, then
the installation itself may introduce oil canning and
other visually unappealing conditions.”

Manufacturing oversize panels is made easy by the large processing area and multihead configurations of the PANELBuilder CNC routing machines. These typically have 72-inch or 84-inch process width, but they can go up to 128 inches or more. Photo courtesy of AXYZ International

Wallace says stiffening and leveling play an important
part in oversized panel installation success. “Larger panels will most likely require stiffeners of some type,” he says. “Know that stiffening isn’t
necessarily there for flatness. It can help somewhat, but really more to meet the performance requirements based on the design loads. [Also,]
start with a properly leveled flat part. Traditionally,
if a fabricator is working with a product that is
subpar in flatness, it could lead to a panel that is
not flat and could result in oil canning. Additionally,
expansion and contraction must be taken very seriously
when building larger panels and ensure that
the design works for the application.”

Art Hance, president of Washington, N.J.-
based Hance Construction Inc., makes sure his
erectors comply with manufacturers’ and industry-recommended
panel installation techniques. “It is critical with longer panels that they are plumb as
just a slight misalignment will be read as a sawtooth
at the bottom of the panel,” he says. “This is
especially noticeable when there is masonry walls
with panels above. We are also seeing issues with
newer high R-value panel systems with longer
fasteners. The longer panels shrink and grow with
temperature differentials and lead to fasteners
failing. This can be exacerbated by improper use of
impact guns for wall fasteners.”